ISU - definition of the skate blade

Rule 500
Definition of the skate blade and clothing
1. Figure Skating blades used during competitions must be sharpened to
produce a flat to concave cross section without change to the width of the blade
as measured between the two edges. However, a slight tapering or narrowing of
the cross section of the blade is permitted

My understanding is that it goes back to the "compulsory figure times". I was told that at one point some skaters "tried" to compete (only in compulsory figures) using different blade profile. It was similar to overturned trapezoid.
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The advantage of this blade profile was to avoid "flats" or "double tracings". The ISU reponse was the "Definition of the skate blade".
I'm just curious if someone knows who were the skaters (or coaches) who "invented" this blade and when it happened.